Method of transmitting control information and device for same

ABSTRACT

The present invention relates to a wireless communication system. In more detail, in relation to an uplink transmission method, the present invention relates to a method which includes: generating a signal for uplink transmission; transmitting the signal by using a subframe #n; if the subframe #n and a subframe #n+1 are subframes for respectively different links, not transmitting the signal in the last symbol of the subframe #n; and if the subframe #n and the subframe #n+1 are subframes for the same link, transmitting the signal by using the last symbol of the subframe #n, and to a device for same.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT/KR2011/007614 filed onOct. 13, 2011, which claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 61/392,924 filed on Oct. 13, 2010, all ofwhich are hereby expressly incorporated by reference into the presentapplication.

TECHNICAL FIELD

The present invention relates to a wireless communication, and moreparticularly, to a method of transmitting control information andapparatus therefor.

BACKGROUND ART

Generally, a wireless communication system is developing to diverselycover a wide range to provide such a communication service as an audiocommunication service, a data communication service and the like. Thewireless communication is a sort of a multiple access system capable ofsupporting communications with multiple users by sharing availablesystem resources (e.g., bandwidth, transmit power, etc.). For example,the multiple access system may include one of CDMA (code divisionmultiple access) system, FDMA (frequency division multiple access)system, TDMA (time division multiple access) system, OFDMA (orthogonalfrequency division multiple access) system, SC-FDMA (single carrierfrequency division multiple access) system and the like.

DISCLOSURE OF THE INVENTION Technical Tasks

One object of the present invention is to provide a method ofefficiently transmitting control information and apparatus therefor.Another object of the present invention is to provide a method ofefficiently transmitting uplink control information in a situation thata plurality of subframes for different links coexist, method ofefficiently managing resources for the same, and apparatus therefor.Technical tasks obtainable from the present invention are non-limitedthe above-mentioned technical task. And, other unmentioned technicaltasks can be clearly understood from the following description by thosehaving ordinary skill in the technical field to which the presentinvention pertains.

Technical Solution

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, inperforming an uplink transmission of a communication apparatus in awireless communication system, a method according to one embodiment ofthe present invention includes the steps of generating a signal for theuplink transmission and transmitting the signal using a subframe #n,wherein if the subframe #n and a subframe #(n+1) are subframes fordifferent links, respectively, the signal is not transmitted in a lastsymbol of the subframe #n and wherein if the subframe #n and thesubframe #(n+1) are subframes for a same link, the signal is transmittedusing the last symbol of the subframe #n.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, a communication apparatus, which isused in a wireless communication system, according to another embodimentof the present invention comprises an RF (radio frequency) unit and aprocessor configured to generate a signal for the uplink transmission,the processor configured to transmit the signal using a subframe #n,wherein if the subframe #n and a subframe #(n+1) are subframes fordifferent links, respectively, the signal is not transmitted in a lastsymbol of the subframe #n and wherein if the subframe #n and thesubframe #(n+1) are subframes for a same link, the signal is transmittedusing the last symbol of the subframe #n.

Preferably, the communication apparatus includes a relay node. Morepreferably, if the subframe #n and the subframe #(n+1) are a backhaulsubframe and an access subframe, respectively, the signal is nottransmitted in the last symbol of the subframe #n. Moreover, if both ofthe subframe #n and the subframe #(n+1) are backhaul subframes, thesignal is transmitted using the last symbol of the subframe #n.

Preferably, the communication apparatus is a user equipment. Morepreferably, if the subframe #n and the subframe #(n+1) are an accesssubframe and a backhaul subframe, respectively, the signal is nottransmitted in the last symbol of the subframe #n. Moreover, if both ofthe subframe #n and the subframe #(n+1) are access subframes, the signalis transmitted using the last symbol of the subframe #n.

Preferably, the signal for the uplink transmission comprises at leastone of an SRS (Sounding Reference Signal), a PUCCH (Physical UplinkControl Channel) signal and a PUSCH (Physical Uplink Shared Channel)signal.

Advantageous Effects

According to the present invention, control information can beefficiently transmitted in a wireless communication system. Inparticular, in case that a plurality of subframes for different linkscoexist, uplink control information can be efficiently transmitted andresources for the same can be efficiently managed.

Effects obtainable from the present invention may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present invention pertains.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 shows one example of physical channels used by a wirelesscommunication system (e.g., 3GPP LTE system) and a general signaltransmitting method using the physical channels.

FIG. 2 shows one example of a structure of a radio frame.

FIG. 3 shows one example of a resource grid of a downlink slot.

FIG. 4 shows a structure of a downlink (hereinafter abbreviated DL)frame.

FIG. 5 shows one example of a structure of an uplink subframe.

FIG. 6 shows one example of mapping PUCCH format to PUCCH regionphysically.

FIG. 7 shows a slot level structure of PUCCH format 2/2a/2b.

FIG. 8 shows a slot level structure of PUCCH format 1a/1b.

FIG. 9 and FIG. 10 show one example of PUCCH format 3.

FIG. 11 shows one example of a wireless communication system including arelay node.

FIG. 12 shows one example of backhaul communication using MBSFN(multimedia broadcast over a single frequency network) subframe.

FIG. 13 and FIG. 14 show examples of a timing configuration between abase station and a relay node applicable to Un uplink.

FIG. 15 shows one example of an operation in case of the setting of thetiming configuration shown in FIG. 14.

FIG. 16 shows one example of backhaul/uplink transmission according toone embodiment of the present invention.

FIG. 17 shows one example of a backhaul/uplink transmitting processaccording to one embodiment of the present invention.

FIG. 18 shows one example of a base station, a relay node and a userequipment, applicable to embodiments of the present invention.

BEST MODE FOR INVENTION

First of all, the following descriptions are usable for various wirelessaccess systems including CDMA (code division multiple access), FDMA(frequency division multiple access), TDMA (time division multipleaccess), OFDMA (orthogonal frequency division multiple access), SC-FDMA(single carrier frequency division multiple access) and the like. CDMAcan be implemented by such a radio technology as UTRA (universalterrestrial radio access), CDMA 2000 and the like. TDMA can beimplemented with such a radio technology as GSM/GPRS/EDGE (Global Systemfor Mobile communications)/General Packet Radio Service/Enhanced DataRates for GSM Evolution). OFDMA can be implemented with such a radiotechnology as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,E-UTRA (Evolved UTRA), etc. UTRA is a part of UMTS (Universal MobileTelecommunications System). 3GPP (3rd Generation Partnership Project)LTE (long term evolution) is a part of E-UMTS (Evolved UMTS) that usesE-UTRA. The 3GPP LTE adopts OFDMA in DL and SC-FDMA in UL.

For clarity, the following description mainly concerns 3GPP LTE/LTE-A,by which the present invention may be non-limited. Moreover, in thefollowing description, specific terminologies are provided to help theunderstanding of the present invention. And, the use of the specificterminology can be modified into another form within the scope of thetechnical idea of the present invention.

In a wireless communication system, a user equipment may be able toreceive information in downlink (DL) from a base station and may be alsoable to transmit information in uplink (UL). Informationtransmitted/received by a user equipment may include data and variouskinds of control information and various kinds of physical channels mayexist in accordance with types and usages of the informationtransmitted/received by the user equipment.

FIG. 1 shows one example of physical channels used by a wirelesscommunication system (e.g., 3GPP LTE system) and a general signaltransmitting method using the physical channels.

If a power of a user equipment is turned on from turn off or the userequipment enters a new cell, the user equipment may perform an initialcell search job for matching synchronization with a base station and thelike [S101]. To this end, the user equipment may receive a primarysynchronization channel (P-SCH) and a secondary synchronization channel(S-SCH) from the base station, may match synchronization with the basestation and may then obtain information such as a cell ID and the like.Subsequently, the user equipment may receive a physical broadcastchannel from the base station and may be then able to obtain intra-cellbroadcast information. Meanwhile, the user equipment may receive adownlink reference signal (DL RS) and may be then able to check a DLchannel state.

Having completed the initial cell search, the user equipment may receivea physical downlink control channel (PDCCH) and a physical downlinkshared control channel (PDSCH) according to the physical downlinkcontrol channel (PDCCH) and may be then able to obtain a detailed systeminformation [S102].

Subsequently, the user equipment may be able to perform a random accessprocedure to complete the access to the base station [S103 to S106]. Tothis end, the user equipment may transmit a specific sequence as apreamble via a physical random access channel (PRACH) [S103] and may bethen able to receive a response message via PDCCH and a correspondingPDSCH in response to the random access [S104]. In case of a contentionbased random access, it may be able to perform a contention resolutionprocedure such as a transmission S105 of an additional physical randomaccess channel and a channel reception S106 of a physical downlinkcontrol channel and a corresponding physical downlink shared channel.

Having performed the above mentioned procedures, the user equipment maybe able to perform a PDCCH/PDSCH reception S107 and a PUSCH/PUCCH(physical uplink shared channel/physical uplink control channel)transmission S108 as a general uplink/downlink signal transmissionprocedure. Control information transmitted to a base station by a userequipment may be commonly named uplink control information (hereinafterabbreviated UCI). The UCI may include HARQ-ACK/NACK (Hybrid AutomaticRepeat and reQuest Acknowledgement/Negative-ACK), SR (SchedulingRequest), CQI (Channel Quality Indication), PMI (Precoding MatrixIndication), RI (Rank Indication) information and the like. In thisspecification, HARQ-ACK is simply named HARQ-ACK or ACK/NACK (AN). TheHARQ-ACK includes at least one of a positive ACK (simply, ACK), anegative ACK (NACK), DTX and NACK/DTX. The UCI is normally transmittedvia PUCCH by periods. Yet, in case that both control information andtraffic data need to be simultaneously transmitted, the UCI may betransmitted on PUSCH. Moreover, the UCI may be non-periodicallytransmitted on PUSCH in response to a request/indication made by anetwork.

FIG. 2 shows one example of a structure of a radio frame. In a cellularOFDM radio packet communication system, UL/DL (uplink/downlink) datapacket transmission is performed by a unit of subframe. And, onesubframe is defined as a predetermined time interval including aplurality of OFDM symbols. In the 3GPP LTE standard, a type-1 radioframe structure applicable to FDD (frequency division duplex) and atype-2 radio frame structure applicable to TDD (time division duplex)are supported.

FIG. 2 (a) shows one example of a structure of a radio frame of type 1.A DL (downlink) radio frame includes 10 subframes. Each of the subframesincludes 2 slots in time domain. And, a time taken to transmit onesubframe is defined as a transmission time interval (hereinafterabbreviated TTI). For instance, one subframe may have a length of 1 msand one slot may have a length of 0.5 ms. One slot may include aplurality of OFDM symbols in time domain or may include a plurality ofresource blocks (RBs) in frequency domain. Since 3GPP system uses OFDMAin downlink, OFDM symbol indicates one symbol duration. The OFDM symbolmay be named SC-FDMA symbol or symbol duration. Resource block (RB) is aresource allocation unit and may include a plurality of contiguoussubcarriers in one slot.

The number of OFDM symbols included in one slot may vary in accordancewith a configuration of CP (cyclic prefix). The CP may be categorizedinto an extended CP and a normal CP. For instance, in case that OFDMsymbols are configured by the normal CP, the number of OFDM symbolsincluded in one slot may be 7. In case that OFDM symbols are configuredby the extended CP, since a length of one OFDM symbol increases, thenumber of OFDM symbols included in one slot may be smaller than that ofthe case of the normal CP. In case of the extended CP, for instance, thenumber of OFDM symbols included in one slot may be 6. If a channelstatus is unstable (e.g., a UE is moving at high speed), it may be ableto use the extended CP to further reduce the inter-symbol interference.

When a normal CP is used, since one slot includes 7 OFDM symbols, onesubframe includes 14 OFDM symbols. In this case, in the front part ofmaximum of 3 OFDM symbols of each subframe may be allocated to PDCCH(physical downlink control channel), while the rest of the OFDM symbolsare allocated to PDSCH (physical downlink shared channel).

FIG. 2 (b) shows one example of a structure of a radio frame of type 2.A type-2 radio frame includes 2 half frames. Each of the half frameincludes 5 subframes, DwPTS (downlink pilot time slot), GP (guardperiod) and UpPTS (uplink pilot time slot). And, one of the subframesincludes 2 slots. The DwPTS is used for initial cell search,synchronization or channel estimation in a user equipment. The UpPTS isused for channel estimation in a base station and uplink transmissionsynchronization of a user equipment. The guard period is a period foreliminating interference generated in uplink due to multi-path delay ofa downlink signal between uplink and downlink.

The above-described structures of the radio frame are just exemplary.And, the number of subframes included in a radio frame, the number ofslots included in the subframe and the number of symbols included in theslot may be modified in various ways.

FIG. 3 shows one example of a resource grid of a downlink slot.

Referring to FIG. 3, a DL slot includes a plurality of OFDM symbols intime domain. One DL slot includes 7(or 6) OFDM symbols and a resourceblock may include 12 subcarriers in frequency domain. Each element on aresource grid is called a resource element (RE). One RB includes 12×7(or 12×6) REs. The number N_(RB) of RBs included in the DL slot dependson a DL transmission band. A structure of a UL slot is identical to thatof the DL slot but OFDM symbol is replaced by SC-FDMA symbol.

FIG. 4 shows one example of a structure of a DL subframe.

Referring to FIG. 4, maximum 3 (or 4) OFDM symbols situated at a headpart of a 1st slot of a subframe correspond to a control region to whicha control channel is assigned. And, the rest of OFDM symbols correspondto a data region to which PDSCH (physical downlink shared channel) isassigned. For example, DL control channels used by 3GPP LTE may includePCFICH (Physical Control Format Indicator Channel), PDCCH (PhysicalDownlink Control Channel), PHICH (Physical Hybrid ARQ Indicator Channel)and the like. The PCFICH is transmitted on a 1st OFDM symbol of asubframe and carries information on the number of OFDM symbols used fora control channel transmission in the subframe. The PHICH carries HARQACK/NACK (acknowledgment/negative-acknowledgment) signal in response toa UL transmission.

Control information transmitted on PDCCH is called DCI (downlink controlinformation). The DCI includes a resource allocation information for auser equipment or a user equipment group and other control information.For instance, the DCI includes UL/DL scheduling information, UL transmit(Tx) power control command and the like.

PDCCH carries transmit format and resource allocation information ofDL-SCH (downlink shared channel), transmit format and resourceallocation information of UL-SCH (uplink shared channel), paginginformation on PCH (paging channel), system information on DL-SCH,resource allocation information of a higher-layer control message suchas a random access response transmitted on PDSCH, Tx power controlcommand set for individual user equipments within a user equipmentgroup, Tx power control command, activation indication information ofVoIP (voice over IP) and the like. A plurality of PDCCHs may betransmitted in a control region. A user equipment may be able to monitora plurality of PDCCHs. PDCCH is transmitted on aggregation of at leastone or more contiguous CCEs (control channel elements). In this case,the CCE is a logical assignment unit used to provide PDCCH with a codingrate based on a radio channel state. The CCE corresponds to a pluralityof REGs (resource element groups). PDCCH format and the number of PDCCHbits are determined depending on the number of CCEs. A base stationdetermines PDCCH format in accordance with DCI to transmit to a userequipment and attaches CRC (cyclic redundancy check) to controlinformation. The CRC is masked with an identifier (e.g., RNTI (radionetwork temporary identifier)) in accordance with an owner or a purposeof use. For instance, if PDCCH is provided for a specific userequipment, CRC may be masked with an identifier (e.g., C-RNTI(cell-RNTI)) of the corresponding user equipment. If PDCCH is providedfor a paging message, CRC may be masked with a paging identifier (e.g.,P-RNTI (paging-RNTI)). If PDCCH is provided for system information(particularly, SIC (system information block)), CRC may be masked withSI-RNTI (system information-RNTI). And, if PDCCH is provided for arandom access response, CRC may be masked with RA-RNTI (randomaccess-RNTI).

FIG. 5 shows one example of a structure of a UL subframe used by LTE.

Referring to FIG. 5, a subframe 500 corresponding to a basic unit of LTEUL transmission includes a pair of 0.5 ms slots 501. Assuming a lengthof a normal CP (cyclic prefix), each of the slots includes 7 symbols 502and each of the symbols corresponds to a single SC-FDMA symbol. Aresource block (RB) 503 is a resource allocation unit. In particular,the resource allocation unit corresponds to 12 subcarriers in frequencydomain and also corresponds to a single slot in time domain. A structureof an uplink subframe of LTE is mainly divided into a data region 504and a control region 505. The data region includes PUSCH and is used totransmit such a data signal as audio and the like. The control regionincludes PUCCH and is used to transmit uplink control information (UCI).The PUCCH includes an RB pair situated at both end portions of the dataregion on a frequency axis and hops using a slot as a boundary.

PUCCH is usable to transmit the control information as follows.

-   -   SR (scheduling request): this is information used to request an        uplink UL-SCH resource. This is transmitted by OOK (on-off        keying).    -   HARQ ACK/NACK: This is a response signal for a DL data packet on        PDSCH. This indicates whether the DL data packet is successfully        received. In response to a single DL codeword, 1-bit ACK/NACK is        transmitted. In response to two DL codewords, 2-bit ACK-NACK is        transmitted.    -   CQI (channel quality indicator): This is the feedback        information on a DL channel. MIMO (multiple input multiple        output) related feedback information includes RI (rank        indicator), PMI (precoding matrix indicator), PTI (precoding        type indicator) and the like. 20 bits are used per subframe.

A size of control information (UCI) transmittable in a subframe by auser equipment depends on the number of SC-FDMAs available for a controlinformation transmission. The SC-FDMA available for the controlinformation transmission means SC-FDMA symbol remaining after excludingSC-FDMA symbol for a reference signal transmission from a subframe. Incase of an SRS (sounding reference signal) configured subframe, a lastSC-FDMA symbol of the subframe is excluded as well. A reference signalis used for coherent detection of PUCCH. And, the PUCCH supports 7formats depending on transmitted information.

Table 1 shows a mapping relation between PUCCH format and UCI in LTE.

TABLE 1 PUCCH format Uplink Control Information (UCI) Format 1SR(Scheduling Request) (non-modulated waveform) Format 1a 1-bit HARQACK/NACK (SR presence/non-presence) Format 1b 2-bit HARQ ACK/NACK (SRpresence/non-presence) Format 2 CQI (20 coded bits) Format 2 CQI & 1- or2-bit HARQ ACK/NACK (20 bits) (corresponding to an extended CP only)Format 2a CQI & 1-bit HARQ ACK/NACK ((20 + 1) coded bits) Format 2b CQI& 2-bit HARQ ACK/NACK ((20 + 2) coded bits)

A sounding reference signal (SRS) is transmitted on SC-FDMA symbollocated last on a time axis in a single subframe. SRSs of several userequipments, which are transmitted on last SC-FDMA of the same subframe,can be identified depending on a frequency position/sequence.

In the legacy LTE, SRS is transmitted by periods. A configuration for aperiodic transmission of SRS is configured with a cell-specific SRSparameter and a UE-specific (user equipment-specific) SRS parameter. Thecell-specific SRS parameter (i.e., cell-specific SRS configuration) andthe UE-specific SRS parameter (i.e., UE-specific SRS configuration) aretransmitted to a user equipment through upper layer (e.g., RRC)signaling. Similarly, in case of a relay node system, an SRSconfiguration for a relay node is configured with a cell-specific SRSparameter and a relay node-specific (RN-specific) SRS parameter.

The cell-specific SRS parameter includes srs-BandwidthConfig andsrs-SubframeConfig. The srs-BandwidthConfig indicates information on afrequency band for transmitting SRS and the srs-SubframeConfig indicatesinformation on a subframe for transmitting SRS. A subframe fortransmitting SRS in a cell is periodically configured within a frame.Table 2 show the srs-SubframeConfig in the cell-specific parameters.

TABLE 2 srs- Bi- Configuration Period Transmission offset SubframeConfignary T_(SFC) (subframes) Δ_(SFC) (subframes) 0 0000 1 {0} 1 0001 2 {0} 20010 2 {1} 3 0011 5 {0} 4 0100 5 {1} 5 0101 5 {2} 6 0110 5 {3} 7 0111 5{0, 1} 8 1000 5 {2, 3} 9 1001 10 {0} 10 1010 10 {1} 11 1011 10 {2} 121100 10 {3} 13 1101 10 {0, 1, 2, 3, 4, 6, 8} 14 1110 10 {0, 1, 2, 3, 4,5, 6, 8} 15 1111 reserved Reserved

The T_(SFC) indicates a cell-specific subframe configuration and theΔ_(SFC) indicates a cell-specific subframe offset. Thesrs-SubframeConfig is provided by an upper layer (e.g., RRC layer). TheSRS is transmitted in a subframe that meets └n_(s)/2┘ modT_(SFC)εΔ_(SFC). The n_(S) indicates a slot index. The └ ┘ indicates aflooring function and the mod indicates a modulo operation.

The UE-specific SRS parameter includes srs-Bandwidth,srs-HoppingBandwidth, freqDomainPosition, srs-ConfigIndex,transmissionComb, and cyclicShift. The srs-Bandwidth indicates a valueused for a corresponding user equipment to configure a frequency bandfor transmitting SRS. The srs-HoppingBandwidth indicates a value used toconfigure frequency hopping of SRS. The FreqDomainPosition indicates avalue used for determine a frequency location for transmitting SRS. Thesrs-ConfigIndex indicates a value used for a corresponding userequipment to configure a subframe for transmitting SRS. ThetransmissionComb indicates a value used to configure an SRS transmissioncomb. And, the cyclicShift indicates a value used to configure a cyclicshift value applied to an SRS sequence.

Table 3 and Table 4 indicate SRS transmission periodicity and subframeoffset in accordance with srs-ConfigIndex. The SRS transmissionperiodicity indicates a time interval (unit: subframe or ms) for a userequipment to periodically transmit SRS. Table 3 shows a case of FDD,while Table 4 shows a case of TDD. An SRS configuration (I_(SRS)) issignaled per user equipment and each user equipment then checks SRStransmission periodicity (T_(SRS)) and SRS subframe (T_(offset)) usingthe SRS configuration index (I_(SRS)).

TABLE 3 SRS Configuration SRS Periodicity SRS Subframe Index I_(SRS)T_(SRS) (ms) Offset T_(offset) 0-1 2 I_(SRS) 2-6 5 I_(SRS)-2   7-16 10I_(SRS)-7  17-36 20 I_(SRS)-17 37-76 40 I_(SRS)-37  77-156 80 I_(SRS)-77157-316 160  I_(SRS)-157 317-636 320  I_(SRS)-317  637-1023 reservedreserved

TABLE 4 Configuration SRS Periodicity SRS Subframe Index I_(SRS) T_(SRS)(ms) Offset T_(offset) 0 2 0, 1 1 2 0, 2 2 2 1, 2 3 2 0, 3 4 2 1, 3 5 20, 4 6 2 1, 4 7 2 2, 3 8 2 2, 4 9 2 3, 4 10-14 5 I_(SRS)-10 15-24 10I_(SRS)-15 25-44 20 I_(SRS)-25 45-84 40 I_(SRS)-45  85-164 80 I_(SRS)-85165-324 160  I_(SRS)-165 325-644 320  I_(SRS)-325  645-1023 reservedreserved

In summary, in the legacy LTE, the cell-specific SRS parameter informs auser equipment of a subframe occupied for SRS transmission in a cell.And, the UE-specific SRS parameter informs the user equipment of asubframe, which is to be actually used by the corresponding userequipment, among the subframes occupied for the SRS. The user equipmentperiodically transmits SRS via a specific symbol (e.g., a last symbol)of the subframe indicated by the UE-specific SRS parameter.

Meanwhile, in order to protect the SRS transmission in the subframeoccupied via the cell-specific SRS parameter, it may be necessary forthe user equipment not to transmit a UL signal via the last symbol ofthe subframe irrespective of whether the SRS is actually transmitted inthe corresponding subframe.

FIG. 6 shows one example of mapping PUCCH format to PUCCH regionphysically.

Referring to FIG. 6, PUCCH format is transmitted by starting from aband-edge in a manner of being inward mapped to RBs in order of PUCCH2/2a/2b (CQI) (e.g., PUCCH region m=0, 1), PUCCH format 2/2a/2b (CQI) orPUCCH format 1/1a/1b (SR/HARQ ACK/NACK) (e.g., in case of presence,PUCCH region m=2), and PUCCH format 1/1a/1b (SR/HARQ ACK/NACK) (e.g.,PUCCH region m=3, 4, 5). The number N_(RB) ⁽²⁾ of PUCCH RBs availablefor PUCCH format 2/2a/2b (CQI) is transmitted to a user equipment bybroadcast signaling within a cell.

FIG. 7 shows a slot level structure of PUCCH format 2/2a/2b. PUCCHformat 2/2a/2b is used for a CSI transmission. And, the CSI includesCQI, PMI, RI and the like. In case of a normal CP (Cyclic Prefix),SC-FDMA #1/#5 (LB #1/#5) within a slot is used for a DM RS (DemodulationReference Signal) transmission. In case of an extended CP, only SC-FDMA#3 (LB #3) within a cell is used for a DM RS transmission.

Referring to FIG. 7, on a subframe level, 10-bit CSI information ischannel coded into 20 coded bits using (20, k) Reed-Muller codepunctured at ½ rate [not shown in the drawing]. Subsequently, the codedbits are scrambled [not shown in the drawing] and then mapped to QPSK(quadrature phase shift keying) constellation [QPSK modulation]. Thisscrambling can be performed using length-31 gold sequence similar to thecase of PUSCH data. 10 QPSK modulated symbols are generated and 5 QPSKmodulated symbols d₀˜d₄ are transmitted via corresponding SC-FDMAsymbols LB #0, LB #2, LB #3, LB #4 and LB #6 in each slot. Each of theQPSK modulated symbols is used to modulate a length-12 sequence(r_(u,O)) before IFFT (Inverse Fast Fourier Transform). Thereafter, eachsequence is cyclically shifted [Cyclic Shift (CS)] (d_(x)*r_(u,O)^((αx)), x=0˜4). Similarly, the DM RS sequence is cyclically shifted aswell (α_(cs,x), x=1, 5). If the number of the cyclic shifts is N, N userequipments can be multiplexed on the same CSI PUCCH RB. The DM RSsequence is similar to a CSI sequence in frequency domain but is notmodulated by the CSI modulated symbol.

A parameter/resource for periodic reporting of CSI is configuredsemi-static by upper layer signaling (e.g., RRC (radio resource control)signaling). For instance, if a PUCCH resource index n_(PUCCH) ⁽²⁾ isconfigured for CSI transmission, CSI is periodically transmitted on CSIPUCCH linked to the PUCCH resource index n_(PUCCH) ⁽²⁾. And, the PUCCHresource index n_(PUCCH) ⁽²⁾ indicates PUCCH RB and cyclic shift(α_(cs)).

FIG. 8 shows a slot level structure of PUCCH format 1a/1b. PUCCH format1a/1b is used for ACK/NACK transmission. In case of a normal CP, SC-FDMA#2/#3/#4 (LB #2/#3/#4) is used for DM RS (Demodulation Reference Signal)transmission. In case of an extended CP, SC-FDMA #2/#3 (LB #2/#3) isused for DM RS transmission. Hence, 4 SC-FDMA symbols in a slot are usedfor ACK/NACK transmission.

Referring to FIG. 8, 1-bit ACK/NACK information and 2-bit ACK/NACKinformation are modulated by BPSK modulation scheme and QPSK modulationscheme, respectively. And, one ACK/NACK modulated symbol d₀ isgenerated. PUCCH format 1a/1b performs cyclic shift (α_(cs,x)) infrequency domain like the aforementioned CSI and also performs timedomain spreading using orthogonal spreading codes w₀, w₁, w₂ and w₃(e.g., Walsh-Hadamard or DFT code). In case of PUCCH format 1a/1b, sincecode multiplexing is used in both frequency and time domains, more userequipments can be multiplexed on the same PUCCH RB.

RSs transmitted from different user equipments are multiplexed by thesame method of UCI. The number of cyclic shifts supported by the SC-FDMAsymbol for PUCCH ACK/NACK RB may be configured by cell-specific upperlayer signaling parameter Δ_(shift) ^(PUCCH). And, Δ_(shift)^(PUCCH)ε{1, 2, 3} indicates that shift values are 12, 6 and 4,respectively. The number of spreading codes actually available forACK/NACK in time-domain CDM may be limited by the number of RS symbols.This is because multiplexing capacity of RS symbols is smaller than thatof UCI symbols due to the small number of RS symbols.

FIG. 9 shows one example of PUCCH format 3 at a slot level. In PUCCHformat 3, a single symbol sequence is transmitted across a frequencydomain and user equipment multiplexing is performed using OCC(orthogonal cover code) based time-domain spreading. In particular, asymbol sequence is transmitted in a manner of being time-domain spreadby OCC. Using OCC, it is able to multiplex control signals of severaluser equipments on the same RB.

Referring to FIG. 9, using OCCs (C1 to C5) of length-5 (i.e., spreadingfactor (SF)=5), 5 SC-FDMA symbols (i.e., UCI data part) are generatedfrom a single symbol sequence {d1, d2, . . . }. In this case, the symbolsequence {d1, d2, . . . } may mean a modulated symbol sequence or acodeword bit sequence. If the symbol sequence {d1, d2, . . . } means thecodeword bit sequence, the block diagram shown in FIG. 9 may furtherinclude a modulated block Although total 2 RS symbols (i.e., RS part)are used in 1 slot in the drawing, it may be able to consider variousapplications such as an application of using RS part configured with 3RS symbols and UCI data part configured using OCC of ‘SF=4’ and thelike. In this case, the RS symbol may be generated from CAZAC sequencehaving a specific cyclic shift. Moreover, the RS may be transmitted in amanner that a specific OCC is applied to a plurality of RS symbols intime domain or a plurality of RS symbols in time domain are multipliedby a specific OCC. Block-spread UCI is transmitted to a network throughFFT (fast Fourier transform), IFFT (inverse fast Fourier transform) bySC-FDMA symbol unit. In particular, the block-spreading scheme modulatesthe control information (e.g., ACK/NACK, etc.) using SC-FDMA unlikePUCCH format 1 or 2 series of the legacy LTE.

FIG. 10 shows one example of PUCCH format 3 at a subframe level.

Referring to FIG. 10, a symbol sequence {d′0˜d′11} in a slot 0 is mappedto a subcarrier of an SC-FDMA symbol and is mapped to 5 SC-FDMA symbolsby block-spreading using OCC (C1 to C5). Similarly, a symbol sequence{d′12˜d′23} in a slot 1 is mapped to a subcarrier of an SC-FDMA symboland is mapped to 5 SC-FDMA symbols by block-spreading using OCC (C1 toC5). In this case, the symbol sequence {d′0˜d′11} or {d′12˜d′23} shownin each slot indicates the form of applying FFT or FFT/IFFT to thesymbol sequence {d1, d2, . . . } shown in FIG. 10. In case that thesymbol sequence {d′0˜d′11} or {d′12˜d′23} has the form of applying FFTto the symbol sequence {d1, d2, . . . } shown in FIG. 10, the IFFT isadditionally applied to the {d′0˜d′11} or {d′12˜d′23} for SC-FDMAgeneration. The whole symbol sequence {d′0˜d′23} is generated by jointcoding at least one UCI. The front half {d′0˜d′11} is transmitted in theslot 0 and the rear half {d′12˜d′23} is transmitted in the slot 1.Besides, the OCC is changeable by slot unit and UCI data can bescrambled by SC-FDMA symbol unit [not shown in the drawing].

FIG. 11 shows one example of a wireless communication system including arelay (or a relay node (RN)). A relay node extends a service area of abase station or is installed in a radio shadow area to smooth a serviceoperation. Referring to FIG. 11, a wireless communication systemincludes a base station, a relay node and a user equipment. The userequipment performs a communication with the base station or the relaynode. For clarity, a user equipment configured to communicate with abase station shall be named a macro user equipment (i.e., a macro UE)and a user equipment configured to communicate with a relay node shallbe named a relay user equipment (i.e., a relay UE). A communication linkbetween a base station and a macro user equipment shall be named a macroaccess link and a communication link between a relay node and a relayuser equipment shall be named a relay access link (simply, a Uu link). Acommunication link between a base station and a relay node shall benamed a backhaul link (simply, a Un link).

Relay nodes can be categorized into L1 (layer 1) relay node, L2 (layer2) relay node and L3 (layer 3) relay node depending on how manyfunctions the corresponding relay node can perform in multi-hoptransmission. Features of the relay nodes are described in brief asfollows. First of all, the L1 relay node performs a function of arepeater. The L1 relay node simply amplifies a signal from a basestation or a user equipment and then transmits the amplified signal tothe user equipment or the base station. Since the relay does not performdecoding, it is advantageous in that a transmission delay is short. Yet,since the relay node is unable to discriminate a signal and a noise fromeach other, it is disadvantageous in that the noise is amplified aswell. In order to complement such disadvantage, it may be able to use anadvanced repeater (or a smart repeater) provided with such a function asa UL power control and a self-interference cancellation. An operation ofthe L2 relay node may be represented as ‘decode-and-forward’ and iscapable of transmitting a user plane traffic to L2 . In the L2 relaynode, it is advantageous in that a noise is not amplified. Yet, it isdisadvantageous in that a delay increases due to decoding. The L3 relaynode may be called self-backhauling and is able to transmit IP packetsto L3. Since the L3 relay node includes an RRC (radio resource control)function, it plays a role as a small-scale base station.

The L1/L2 relay node may be described as a case that a relay node is apart of a donor cell covered by a corresponding base station. In casethat a relay node is a part of a donor cell, since the relay node isunable to control a cell of its own and user equipments of thecorresponding cell, the relay node is unable to have a cell ID of itsown. Yet, the relay node may have a relay ID that is an ID (identity) ofthe corresponding relay node. Moreover, in this case, some functions ofRRM (radio resource management) are controlled by a base station of thecorresponding donor cell and some portions of the RRM may be situated atthe corresponding relay node. The L3 relay node corresponds to a casethat a relay node is able to control its cells. In this case, the relaynode is able to manage at least one cell and each of the cells managedby the relay node may be able to have a unique physical-layer cell ID.The relay node may have the same RRM mechanism. And, in viewpoint of auser equipment, there is no difference between accessing a cell managedby a relay node and accessing a cell managed by a normal base station.

Relay nodes can be classified in accordance with mobility as follows.

-   -   Fixed relay node (fixed RN): This is permanently fixed and used        for shadow area or cell coverage enhancement. This is able to        play a role as a simple repeater.    -   Nomadic relay node (nomadic RN): This is temporarily installed        in case of a sudden increase of users. This is randomly movable        within a building.    -   Mobile relay node (mobile RN): This is installable on such a        public transportation as a bus, a subway and the like. This        needs to be supported with relay mobility.

Relays can be classified into in accordance with a link of a network asfollows.

-   -   In-band connection: A network-to-relay link and a        network-to-user equipment link share the same frequency band        with each other in a donor cell.    -   Out-band connection: A network-to-relay link and a        network-to-user equipment link use different frequency bands in        a donor cell, respectively.

Relays can be classified as follows, depending on whether a userequipment recognizes a presence of a relay node.

-   -   Transparent relay node: A user equipment is unaware whether a        communication with a network is performed via a relay node.    -   Non-transparent relay node: A user equipment is aware that a        communication with a network is performed via a relay node.

FIG. 12 shows one example of backhaul transmission using MBSFN(multimedia broadcast over a single frequency network) subframe. In anin-band relay mode, a BS-RN link (i.e., a backhaul link) operates on thesame frequency band of an RN-UE link (i.e., a relay access link). When arelay node transmits a signal to a user equipment while receiving asignal from a base station, and vice versa, since a transmitter and areceiver of the relay node trigger mutual interference, the relay nodemay be restricted from performing the transmission and the reception atthe same time. To this end, the backhaul link and the relay access linkare partitioned by TDM scheme. In order to support a measurementoperation of a legacy LTE user equipment existing in a relay zone, LTE-Aconfigures a backhaul link in MBSFN subframe [Fake MBSFN Method]. If arandom subframe is signaled to an MBSFN subframe, since a user equipmentreceives a control region (ctrl) of the corresponding subframe, a relaynode is able to configure a backhaul link using a data region of thecorresponding subframe. For instance, a relay PDCCH (R-PDCCH) istransmitted using a specific resource region within a 3^(rd) OFDM symbolto a last OFDM symbol of the MB SFN subframe.

In order to raise BS-RN/RN-UE radio link efficiency, a network includinga relay node uses various kinds of synchronization schemes. According toone of the synchronization schemes, a boundary of a UL subframe receivedby a base station from a relay node is made to coincide with a basestation UL subframe boundary. If the subframe boundaries coincide witheach other, it can be represented as aligned. Meanwhile, a relay node isunable to simultaneously perform both a DL reception and a DLtransmission using the same carrier. Hence, the relay node needs tooperate by switching two kinds of transmission modes to each other. Inorder to switch the transmission mode, a time, i.e., a TX-to-RXswitching time or an RX-to-TX switching time, is necessary. A time lossportion due to the transmission mode switching may be obtained from abackhaul link or a relay access link. In case that the time loss portionis obtained from the backhaul link, some of backhaul symbols may beusable for a switching time by being configured in a guard time form.Since the guard time configured symbol is not usable for the datatransmission, it is wasted.

FIG. 13 and FIG. 14 show examples of a timing configuration between abase station and a relay node applicable to Un uplink. In the drawings,if a boundary of a relay backhaul UL subframe and a boundary of a relayaccess link UL subframe are misaligned, it is able to increaseefficiency in using resources of a backhaul link. It may be able toadjust a boundary of a subframe using a propagation delay Tp and a timeoffset To. The time offset To may indicate a delay or an advance. Thetime offset To may have a fixed value. In the drawings, ‘macro’indicates a macro UL subframe, ‘backhaul’ indicates a backhaul ULsubframe, and ‘access’ indicates a relay access UL subframe. Moreover, aTX-to-RX switching time and an RX-to-TX switching time are denoted by G1and G2, respectively.

According to the timing configurations shown in FIG. 13 and FIG. 14, anindex of a last symbol available for a UL transmission in a 2^(nd) slotis 5 or 6 (in case of a normal CP). In case of an extended CP, the indexof the last symbol is 4 or 5. In particular, the index of the lastsymbol available for the UL transmission in the 2^(nd) slot becomes 6according to the timing configuration shown in FIG. 13 but becomes 5according to the timing configuration shown in FIG. 14. And, the timingconfiguration shown in FIG. 13 or FIG. 14 may be configured by upperlayer signaling (e.g., RRC signaling).

FIG. 15 shows one example of an operation in case of the setting of thetiming configuration shown in FIG. 14.

Referring to FIG. 15, in case of the setting of the timing configurationshown in FIG. 14, a relay node is unable to use the last symbol (i.e.,symbol #6) of the 2^(nd) slot for the transmission of PUSCH/PUCCHsignal. Meanwhile, if it is unable to use the last symbol of the 2^(nd)slot, it may be able to use a rate matching not to use the last symbolin the 2^(nd) slot in case of PUSCH. Moreover, in case of PUCCH format1/1a/1b, a shortened format of not using the last symbol in the 2^(nd)slot is defined in the legacy LTE. Hence, in case that the timingconfiguration shown in FIG. 14 is signaled, the PUSCH signal is ratematched and a PUCCH format 1/1a/1b signal can be transmitted using theshortened PUCCH format.

Yet, in case of PUCCH format 2/2a/2b, the shortened format is notdefined in the legacy LTE unlike the PUCCH format 1/1a/1b. Moreover,PUCCH format 3 is the PUCCH format newly introduced into LTE-A. Like thePUCCH format 2/2a/2b, the shortened format is not defined in the PUCCHformat 3. Hence, in case of the setting of the timing configurationshown in FIG. 14, a separate transmitting method is necessary totransmit a PUCCH format 2/2a/2b/3 signal in backhaul/uplink. Simply, ina situation that the last symbol of the 2^(nd) slot is not usable, it isable to puncture a last symbol of the PUCCH format 2/2a/2b/3 signal.Since a base station and a relay node is able to know the situation inwhich the last symbol of the Un link (i.e., BS-RN link) is nottransmittable due to the TX/RX switching, the base station is able todecode the PUCCH format 2/2a/2b/3 signal in consideration of puncturing.If the shortened format is defined in the PUCCH format 2/2a/2b/3, it maybe able to use the defined shorted format.

Yet, in case that the timing configuration shown in FIG. 14 is set, itis possible to transmit PUSCH/PUCCH signal in backhaul/UL without usingthe rate matching or the shortened format.

FIG. 16 shows one example of backhaul/uplink transmission according toone embodiment of the present invention.

Referring to FIG. 16, if a least two backhaul subframes (e.g., subframe#n and subframe #(n+1)) are contiguously configured, since the TX/RXswitching is not performed between the backhaul subframes (i.e.,subframe #n and subframe #(n+1)), it may be able to use a last symbol ofthe former backhaul subframe (i.e., subframe #n) for a backhaultransmission. Therefore, it is able to perform a transmission of SRS, anormal-length PUCCH or a normal-length PUSCH in the last symbol of theformer backhaul subframe (subframe #n). In order to enable such anoperation, an agreement between a base station and a relay node isnecessary. In particular, information indicating whether the last symbolin the 2^(nd) slot (or subframe) is used and/or information on thecorresponding operation needs to be exchanged or agreed in advancebetween the base station and the relay node. The information indicatingwhether the last symbol in the 2^(nd) slot (or subframe) is used and/orthe information on the corresponding operation is configured by an upperlayer signaling (e.g., an RRC signaling) or may be implicitly designateddepending on transmission mode/configuration mode/timingconfiguration/backhaul subframe configuration.

As mentioned in the foregoing description, in case that contiguousbackhaul subframes exist in the timing configuration shown in FIG. 14,the relay node may be able to always transmit SRS, last symbol of PUCCHor last symbol of PUSCH in the former backhaul subframe (subframe #n).The relay node is able to transmit the SRS only if the SRS configured tobe transmitted in the corresponding subframe. In particular, in casethat the RN-specific SRS configured subframe and the contiguous backhaulsubframe do not coincide with each other, the SRS is not transmitted.Meanwhile, if the contiguous backhaul subframes are configuredirrespective of the previous SRS configuration signaling, the relay nodeis able to always transmit the SRS in the former subframe (subframe #n).In this case, the base station may be able to intentionally configurecontiguous backhaul subframes for the backhaul SRS transmission.

It is possible for the transmission of PUCCH/PUSCH to perform theoperation similar to that of the SRS. In particular, if contiguousbackhaul subframes (subframe #n and subframe #(n+1)) are assigned forthe backhaul transmission, the former backhaul subframe (subframe #n)autonomously uses PUCCH/PUSCH of a normal length. If a single subframeis assigned for the backhaul transmission, it may be able to use theshortened subframe structure. In case that a plurality of contiguoussubframes are assigned for the backhaul transmission, operations of arelay node and a base station should be designated in advance. In otherwords, in case that a plurality of contiguous subframes are assigned forthe backhaul transmission, it may be able to designate the normal PUCCH,PUSCH and SRS transmissions, which are to be unconditionally performedin the former backhaul subframe, in advance by signaling or implicitly.Moreover, it may be able to set such an operation to be enabled ordisabled by a separate upper layer signaling (e.g., RRC signaling).

For instance, if backhaul subframes are contiguously generated, it maybe able to set the SRS to be always transmitted in the former backhaulsubframe (subframe #n) irrespective of SRS configuration [autonomoustransmission=ON]. Alternatively, although backhaul subframes arecontiguously configured, it may be able to set the SRS not to betransmitted in the former backhaul subframe [autonomoustransmission=OFF]. Likewise, if backhaul subframes are contiguouslyconfigured, it may be able to set a normal PUCCH format to be used inthe former backhaul subframe [shortened format=OFF]. Alternatively,although backhaul subframes are contiguously configured, it may be ableto set the shortened format to be used [shortened format=ON]. In case ofthe PUSCH transmission, if backhaul subframes are contiguouslyconfigured, it may be able to set a last symbol of a subframe to be usedfor a PUSCH signal transmission in the former backhaul subframe [ratematching=OFF]. Alternatively, although backhaul subframes arecontiguously configured, it may be able to set the last symbol of thesubframe not to be used for the PUSCH signal transmission [ratematching=ON].

It may be able to deliver the above-mentioned information (e.g.,‘autonomous transmission’, ‘shortened format’, ‘rate matching’, etc.)using RRC signaling. In this case, although the aforementionedinformation is not frequently changeable, since Un subframeconfiguration does not change frequently, it can be implemented with theRRC signaling. If the aforementioned information is set to a specificvalue and backhaul subframes are contiguously configured, a relay nodedetermines a transmission form of a UL signal in accordance with thesetup value and then performs a corresponding operation.

FIG. 17 shows one example of a backhaul/uplink transmitting processaccording to one embodiment of the present invention.

Referring to FIG. 17, a relay node configures a backhaul subframe[S1702]. The backhaul subframe may be indicated as a bitmap form by anupper layer signaling (e.g., RRC signaling). Each bit of a bitmapcorresponds to a subframe. In particular, if a corresponding bit is setto 1, a backhaul subframe is configured. If a corresponding bit is setto 0, an aces subframe may be configured. A separate bitmap may bedefined for UL and DL backhaul subframes. Moreover, a bitmap for a DLbackhaul subframe is signaled only and a UL backhaul subframe may beanalogized from a DL backhaul subframe configuration. For instance, if aDL subframe #m is configured as a DL backhaul subframe, a UL subframe#(m+4) may be configured as a UL backhaul subframe. Subsequently, therelay node generates a UL signal for a UL backhaul subframe #n [S1704].UL signal may include SRS signal, PUCCH signal and PUSCH signal.

Thereafter, the relay node checks whether the UL subframe #(n+1) is a ULbackhaul subframe [S1706]. If the UL subframe #(n+1) is the UL backhaulsubframe, the relay node is able to use a last symbol of the UL backhaulsubframe #n for a signal transmission [S1708]. Hence, an SRS signaltransmission, a normal PUCCH signal transmission and a normal PUSCHsignal transmission are possible. On the contrary, if the UL subframe#(n+1) is not the UL backhaul subframe, the relay node is unable to usethe last symbol of the UL backhaul subframe #n for the signaltransmission [S1710]. Therefore, the SRS signal transmission is droppedand a PUCCH signal is transmitted using a shortened PUCCH format or arate-matched PUSCH signal transmission is possible.

Meanwhile, if the UL subframe #n is a subframe configured as anRN-specific SRS subframe despite being configured as a cell-specific SRSsubframe, although the UL subframe #(n+1) is a UL backhaul subframe, alast symbol of the subframe may not be usable. This is because, in caseof the subframe configured as the RN-specific SRS subframe despite beingconfigured as the cell-specific SRS subframe, the relay node may nottransmit the last symbol to protect an SRS transmission of another relaynode/user equipment. In case that the last symbol of the UL subframe #nis not usable in accordance with the SRS configuration, the relay nodeshould puncture a last symbol of the PUCCH/PUSCH signal (e.g., shortenedformat). The base station knows a fact that there is no signaltransmission in the last symbol and should perform demodulation/decodingby reflecting the fact.

In the present example, the step S1706 and the step S1708 may beoptionally or selectively applicable by an upper layer signaling (e.g.,an RRC signaling) or in accordance with a specific condition. Inparticular, if the operations in the step S1706 and the step S1708 areset not to be performed, the step S1706 and the step S1708 may beexcluded from the process shown in FIG. 17. The application of the stepS1706 and the step S1708 may be independently set in accordance with atype of a UL Signal. For instance, it may be able to determine whetherto apply the step S1706 and the step S1708 depending on “autonomoustransmission=ON/OFF” (SRS), “shortened format=ON/OFF” (PUCCH), and “ratematching=ON/OFF” (PUSCH).

The above description a made centering on the Un link (i.e., BS-RNlink). Yet, the above-described method is applicable to a case oftransmitting SRS signal, PUCCH signal or PUSCH signal in the Uu link(i.e., RN-UE link). In particular, if a subframe #n is a Uu subframe(i.e., an access subframe) and a subframe #(n+1) is a Un subframe (i.e.,a backhaul subframe), a user equipment is unable to transmit a lastsymbol of the Uu subframe. Due to such restriction, some restrictionsare put on SRS signal transmission, PUCCH signal transmission and PUSCHsignal transmission of the user equipment. In order for the userequipment to transmit the last symbol of the Uu subframe, the subframe#(n+1) is not set as the Un subframe or set as the Uu subframe. Inparticular, in case that Uu subframes are contiguously configured, theuser equipment is able to transmit an SRS signal, a normal PUCCH signaland a normal PUSCH signal in the former Uu subframe. The detailed methodis identical to the former description in association with the Un link.In particular, if a backhaul is replaced by an access in FIG. 17, theprocess shown in FIG. 17 is extended to a process for Un/ULtransmission. And, the step S1706 shown in FIG. 17 can be generalizedinto a step of determining whether the subframe #n and the subframe#(n+1) are subframes for different links or for the same link. In caseof the process for the relay node, the step S1706 shown in FIG. 17determines whether the subframe #(n+1) is a backhaul subframe if thesubframe #n is a backhaul subframe. On the contrary, in case of theprocess for the user equipment, the step S1706 shown in FIG. 17determines whether the subframe #(n+1) is an access subframe if thesubframe #n is an access subframe.

The above-mentioned description is not limited to the case that one lastsymbol of a subframe is not transmittable. The present invention can beextended to a case that it is unable to transmit m contiguous symbols atthe end of the subframe. And, the present invention is applicable to acase that it is unable to transmit a front part of the subframe (e.g., a1^(st) symbol of the subframe, a 2^(nd) symbol of the subframe, etc.).

In addition, in the mode of puncturing and transmitting the last symbol,i.e., in case of transmitting a CQI having a shortened length, the basestation should know the fact that the CQI is not present at the lastsymbol and should perform demodulation by reflecting the fact.

In particular, in case that the RN-specific SRS configuration is notperformed despite the cell-specific subframe, the relay node does nottransmit SRS but is able to perform a CQI transmission. Yet, if thetiming configuration is unable to use the last symbol, it causes aproblem of CQI transmission and reception. If a CQI is transmitted in afull subframe, it may miss a switching timing point (e.g., a case that anext subframe is a Uu subframe). Hence, the relay node has to transmitthe CQI except the last symbol. The base station is able to successfullyperform the demodulation only if knowing such a situation. In case ofPUCCH format 3, the similar problem is caused. If there exists aparameter for enabling a shortened format of the PUCCH format 3, ashortened PUCCH format 3 is used in the aforementioned problematicsubframe using the existing parameter. If the cell-specific orRN-specific SRS configuration is used, the PUCCH format 3 should betransmitted by being punctured. And, the base station should be aware ofthis situation. This technology may be similarly applicable to the Uusituation.

FIG. 18 shows one example of a base station, a relay node and a userequipment, applicable to embodiments of the present invention.

Referring to FIG. 18, a wireless communication system includes a basestation (BS) 110, a relay node (RN) 120 and a user equipment (UE) 130.For clarity, the user equipment is connected to the relay node in thedrawing. Instead, the user equipment may be connected to the basestation.

The base station 110 includes a processor 112, a memory 114 and a radiofrequency (RF) unit 116. The processor 112 may be configured toimplement the procedures and/or methods proposed by the presentinvention. The memory 114 is connected to the processor 112 and storesvarious kinds of information related to operations of the processor 112.The RF unit 116 is connected to the processor 112 and receives and/ortransmits wireless signals. The relay node 120 includes a processor 122,a memory 124 and an RF unit 126. The processor 122 may be configured toimplement the procedures and/or methods proposed by the presentinvention. The memory 124 is connected to the processor 122 and storesvarious kinds of information related to operations of the processor 112.The RF unit 126 is connected to the processor 122 and receives and/ortransmits wireless signals. The user equipment 130 includes a processor132, a memory 134 and an RF unit 136. The processor 132 may beconfigured to implement the procedures and/or methods proposed by thepresent invention. The memory 134 is connected to the processor 132 andstores various kinds of information related to operations of theprocessor 132. The RF unit 136 is connected to the processor 132 andreceives and/or transmits wireless signals. Each of the base station110, the relay node 120 and the user equipment 130 may have a singleantenna or multiple antennas.

The above-described embodiments may correspond to combinations ofelements and features of the present invention in prescribed forms. And,it may be able to consider that the respective elements or features maybe selective unless they are explicitly mentioned. Each of the elementsor features may be implemented in a form failing to be combined withother elements or features. Moreover, it may be able to implement anembodiment of the present invention by combining elements and/orfeatures together in part. A sequence of operations explained for eachembodiment of the present invention may be modified. Some configurationsor features of one embodiment may be included in another embodiment orcan be substituted for corresponding configurations or features ofanother embodiment. And, it is apparently understandable that a newembodiment may be configured by combining claims failing to haverelation of explicit citation in the appended claims together or may beincluded as new claims by amendment after filing an application.

In this disclosure, embodiments of the present invention are describedcentering on the data transmission/reception relations between a basestation and a user equipment. In this disclosure, a specific operationexplained as performed by a base station may be performed by an uppernode of the base station in some cases. In particular, in a networkconstructed with a plurality of network nodes including a base station,it is apparent that various operations performed for communication witha user equipment may be performed by a base station or other networks(e.g., relay, etc.) except the base station. In this case, ‘basestation’ can be replaced by such a terminology as a fixed station, aNode B, an eNode B (eNB), an access point and the like. And, ‘terminal’may be replaced by such a terminology as a user equipment (UE), a mobilestation (MS), a mobile subscriber station (MSS)’ and the like.

Embodiments of the present invention may be implemented using variousmeans. For instance, embodiments of the present invention may beimplemented using hardware, firmware, software and/or any combinationsthereof. In case of the implementation by hardware, one embodiment ofthe present invention may be implemented by one of ASICs (applicationspecific integrated circuits), DSPs (digital signal processors), DSPDs(digital signal processing devices), PLDs (programmable logic devices),FPGAs (field programmable gate arrays), processor, controller,microcontroller, microprocessor and the like.

In case of the implementation by firmware or software, one embodiment ofthe present invention may be implemented by modules, procedures, and/orfunctions for performing the above-explained functions or operations.Software code may be stored in a memory unit and may be then drivable bya processor. The memory unit may be provided within or outside theprocessor to exchange data with the processor through the various meansknown to the public.

While the present invention has been described and illustrated hereinwith reference to the preferred embodiments thereof, it will be apparentto those skilled in the art that various modifications and variationscan be made therein without departing from the spirit and scope of theinvention. Thus, it is intended that the present invention covers themodifications and variations of this invention that come within thescope of the appended claims and their equivalents. For instance, therespective configurations disclosed in the aforesaid embodiments of thepresent invention can be used by those skilled in the art in a manner ofbeing combined with one another. Therefore, the present invention isnon-limited by the embodiments disclosed herein but intends to give abroadest scope matching the principles and new features disclosedherein.

Industrial Applicability

Accordingly, the present invention is applicable to such a wirelesscommunication device as a user equipment, a relay node, a base stationand the like.

What is claimed is:
 1. A method for performing an uplink transmission ofa communication apparatus in a wireless communication system, the methodcomprising: receiving control information from a base station by highlayer signaling; generating a sounding reference signal (SRS) for theuplink transmission; and transmitting the SRS using a subframe #n,wherein the SRS is transmitted on a symbol located last on a time axisin the subframe #n, wherein if the subframe #n and a subframe #(n+1) aresubframes for different links, respectively, the SRS is not transmittedin a last symbol of the subframe #n, wherein if the subframe #n and thesubframe #(n+1) are subframes for a same link, the SRS is transmittedusing the last symbol of the subframe #n when the subframe #n is asubframe configured as a relay node (RN)-specific SRS subframe, whereinif the subframe #n and the subframe #(n+1) are subframes for the samelink, the SRS is not transmitted in a last symbol of the subframe #nwhen the subframe #n is a subframe configured as a cell-specific SRSsubframe, and wherein the control information includes information onwhether the last symbol of the subframe #n is used for transmission ofthe signal.
 2. The method of claim 1, wherein the communicationapparatus is a relay node.
 3. The method of claim 2, wherein if thesubframe #n and the subframe #(n+1) are a backhaul subframe and anaccess subframe, respectively, the SRS is not transmitted in the lastsymbol of the subframe #n, and wherein if both of the subframe #n andthe subframe #(n+1) are backhaul subframes, the SRS is transmitted usingthe last symbol of the subframe #n.
 4. The method of claim 1, whereinthe communication apparatus is a user equipment.
 5. The method of claim4, wherein if the subframe #n and the subframe #(n+1) are an accesssubframe and a backhaul subframe, respectively, the SRS is nottransmitted in the last symbol of the subframe #n, and wherein if bothof the subframe #n and the subframe #(n+1) are access subframes, the SRSis transmitted using the last symbol of the subframe #n.
 6. Acommunication apparatus, which is used in a wireless communicationsystem, the communication apparatus comprising: an RF (radio frequency)unit; and a processor configured to receive control information from abase station by high layer signaling, wherein the processor is furtherconfigured to: generate a sounding reference signal (SRS) for the uplinktransmission, and transmit the SRS signal-using a subframe #n, whereinthe SRS is transmitted on a symbol located last on a time axis in thesubframe #n, wherein if the subframe #n and a subframe #(n+1) aresubframes for different links, respectively, the SRS is not transmittedin a last symbol of the subframe #n when the subframe #n is a subframeconfigured as a relay node (RN)-specific SRS subframe, wherein if thesubframe #n and the subframe #(n+1) are subframes for a same link, theSRS is not transmitted in a last symbol of the subframe #n when thesubframe #n is a subframe configured as a cell-specific SRS subframe,and wherein the control information includes information on whether thelast symbol of the subframe #n is used for transmission of the signal.7. The communication apparatus of claim 6, wherein the communicationapparatus is a relay node.
 8. The communication apparatus of claim 7,wherein if the subframe #n and the subframe #(n+1) are a backhaulsubframe and an access subframe, respectively, the SRS is nottransmitted in the last symbol of the subframe #n, and wherein if bothof the subframe #n and the subframe #(n+1) are backhaul subframes, theSRS is transmitted using the last symbol of the subframe #n.
 9. Thecommunication apparatus of claim 6, wherein the communication apparatusis a user equipment.
 10. The communication apparatus of claim 9, whereinif the subframe #n and the subframe #(n+1) are an access subframe and abackhaul subframe, respectively, the SRS is not transmitted in the lastsymbol of the subframe #n, and wherein if both of the subframe #n andthe subframe #(n+1) are access subframes, the SRS is transmitted usingthe last symbol of the subframe #n.